1. Field of the Invention
The present invention relates to a touch type display device and, more particularly, to a touch type display device capable of maximizing a signal-to-noise ratio (SNR) in a solar light environment.
2. Description of the Related Art
Recently, as the electronic technology is being rapidly developed, user expectation with respect to display devices having various functions is growing, and in order to meet such user demand, research on a touch type display device available for image conversion by using a touch function applied thereto without an external input device such as a mouse and the like is actively ongoing.
There are various types of touch type display devices including a resistive film type touch display device, a capacitance touch type display device, an electromagnetic induction touch type display device, and the like, according to how coordinates of a touched point are recognized. Recently, a touch type display device for recognizing coordinates of a touched point by using infrared. The touch type display device using infrared can be easily applied to a large-scale display device and easily recognize a multi-touch, so its application coverage widens.
The touch type display device using infrared includes a flat panel display module, an infrared light emitting diode disposed at a portion of an edge of the flat panel display module, and an infrared camera disposed at two corners of the flat panel display module.
In the related art general touch type display device having such configuration, when a user touches a certain point of the screen of the flat panel display module with his finger (or an indication rod), infrared ray emitted from an infrared light emitting diode (LED) of the touched point is covered by the user's finger, so an infrared camera receives no infrared ray at the corresponding touched point. The infrared camera transfers the touch-related information to a controller, and the controller analyzes the touch-related information to determine coordinates of the touched point.
The related art general touch type display device has a problem in that unnecessary external light is recognized by the infrared camera.
Namely, infrared light emitted from the infrared LED has a certain wavelength range, and a distribution of the external light (i.e., noise) is different from that of the infrared light emitted from the LED, resulting in an increase of the SNR of the light,